Desensitizer and process of desensitizing light-sensitive photographic materials



Patented Apr. 8, 1930 UNITED STATES PATENT OFFICE BRUNO WENDT, OI DESSA U annanmennmm, ASSIG-NOR TO AGFA ANSCO COR- PORATION, OF IBINGHAM'ION, NEW YORK, A CORPORATION OF NEW YORK DESENSITIZER AND PROCESS OF DESENSITIZINQ LIGHT-SENSITIVE PHOTOGBAPHIC MATERIALS No Drawing. Application filed December 28, 1928,. Serial No. 329,070, and in Germany February 3, 1928.

The present invention relates to new desensitizing compounds for light sensitive photographic materials, more particularly it relates to the employment of polynuclear quinones as desensitlzers for silver halid emulsions.

These polynuclear quinones, especially anthraquinones and phenanthraquinones, have a powerful desensitizing effect and are more powerful than the quinones of the benzene series. They are particularly applicable for desensitizing panchromatic emulsions.

In the groups of anthraquinones and phenanthraquinones are substances which are active desensitizers and are at the same time not liable to color the photographic layer, though, of course, there are also bodies having the properties of dyestufls and the latter can beused in particular cases where coloration of the photographic layer is not objectionable.

Since the desensitizer must be used in aqueous solution the anthraquinone or phenanthraquinone derivative selected should be soluble in water for example it may be the sodium salt of the sulfonic acid.

The desensitizer may be usedin a preliminarybath or may be added to the developer solution. In the latter case very small proportions added will suflice for a; considerable des'ensitizing so that the developer solution is not injuriously aflected.

The following examples illustrate the invention:

Ewample 1.-An exposed panchromatic plate or film is immersed for 2 minutes in -Jh'e dark in a solution of sodium'l-nitroanthraquinone-2-carboxylate (1 400). It ma then be developed in red light. j

wa'rnple .@.--A solution of alizarine direct blue B (Schultz, Farbstofitabellen, 5th edition, No. 851) of 0.1 per cent stren h, may be used in the manner described in xample 1.

Ewample 3.-To a suitable developer sodium anthraquinone-Q-sulfonate is added so as to make its concentration in the solution 1 :3000. The photographic film is immersed in this developer for 2 minutes in the dark quinone.

and can then be further developed in red light.

I claim:

1. A process which comprises desensitizing. light sensitive photographic materialsby treating them with an aqueous solution of a polynuclear quinone derivative.

2. A process which comprises desensitizing light sensitive photographic materials by treating them with an aqueous solution of a polynuclear quinone containing a salt forming group.

3. A process which comprises desensitizing light sensitive photographic materials by treating them with an aqueous solution of a salt of an acid derived from a polynuclear 4- A process which comprises desensitizing light sensitive photographic materials by treating them with an aqueous solution of a salt of an acidderived, from a polynuclear quinone containing at least one nitro-group.

5. A' processwhich comprises desensitizing light sensitive photographic materials by treating them with an aqueous solution of a salt of a sulfonic acid derived from a polynuclear quinone containing at least one nitrogroup.

6. A process which comprises desensitizing light sensitive photographic materials by treating them with an aqueous solution of a quinone derivative of the anthracene series. 7. A process which comprises desensitizing light sensitive photographic materials by treating them with an aqueous solution of a quinone derivative of the anthracene series containing a salt forming group.

8. A process which comprises desensitizing light sensitive photographic materials by treating them with an aqueous solution'of a salt of an acid derived from anthraquinone.

9. A process which comprises desensitizing light sensitive photographic materials by treating them with an aqueous solution of a salt of a sulfonic acid of anthraquinone.

10. A process which comprises desensitizing light sensitive photographic materials by treating them with an aqueous solution of a salt of a mono-sulfonic acid of anthraquinone.

11. A process which comprises desensitizing light sensitive photographic materials by treating them with an aqueous solution of a salt of the anthraquinone-2-sulfonic acid.-

5 12. A process which comprises desensitizing light sensitive photographic materials by treating them with an aqueous solution of sodium anthraquinone-Q-sulfonate.

13. As a desensitizer a polynuclear quinone derivative soluble in water- 14. As a desensitizer a polynuclear quinone containing a salt forming group.

15. As a desensitizer a salt of an acid derived from a polynuclear quinone.

16. As a desensitizer a salt of an acid derived from a polynuclear quinone containing at least one nitro-group.

17 As a desensitizer a salt of a sulfonic acid derived from a polynuolear quinone con- 20 taining at least one nitro-group.

18. As a desensitizer a quinone derivative of the anthracene series.

19. As a desensitizer a quinone derivative of the anthracene series containing a salt s forming group.

20. As a desensitizer a salt of an acid derived from anthraquinone.

21. As a desensitizer a salt of a sulfonic acid of anthraquinone.

22. As a desensitizer a salt of a mono-sulfonic acid of anthraquinone' 23- As adesensitizer a salt of the anthraquinone-2-sulfonic acid.

24. As a desensitizer sodium anthraquinone-2-sulfonate.

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